Multi-beam convergence controlling systems



3 Sheets-Sheet 1 Sept. 5, 1961 D. H. PR|TCHARD ETAL BEAM coNvERGENcE CONTROLLING SYSTEMS MULTI- Filed April 7, 1953 .f @5 if Sept. 5, 1961 D. H. PRITCHARD ETAL 2,999,186

MULTI-BEAM coNvERGENcE coNTRoLLrNG SYSTEMS Filed April 7, 1953 3 Sheets-Sheet 2 w W WMM N .3+ m Ww N f m P h lw A Q M wm NN N H MM W 3Q A//D .mm W l mmv l Q `\N NX NN H kmw ,.PVNM V ww w w NQ. w N N m. Mn f i r flvv Aw Q V l@ K/mvww Sept. 5, 1961 D. H. PRITCHARD ET AL 2,999,186

MULTI-BEAM CONVERGENCE CONTROLLING SYSTEMS Filed April 7. 195s s sheets-sheet s MMP/5.2), /Vasa/ United States-Patent "i p 2,999,186 MULTI-BEAM CONVERGENCE CONTROLLING SYSTEMS Dalton H. Pritchard, Princeton, NJ., and Morris David Nelson, New York, NX., assignors to Radio Corpor tion of America, a corporation of Delaware Filed Apr. 7, 1953, Ser. No. 347,284

22 Claims. (Cl. 315-13) l This invention relates .to systems for controlling the directivity of electron beam energyof cathode ray tubes. It pertains particularly to the control of a plurality of electron beam components used in television kinescopes so as to effect substantial convergence of the beam components at all points of a raster scanned at a target electrode. i

One type of cathode ray tube,in which there is encountered the problem of maintaining substantial con'- vergence of a plurality of beam components at a' target electrode, is a color kinescope such as .that disclosed in a paper by H. B. Law titled A Three-Gun Shadow-Mask Color Kinescope published in the Proceedings, of`the IRE, vol. 39, No. 10, October 1951, at page 1186. Such a tube has a luminescent screen consisting of a multiplicity of phosphor areas of sub-elemental dimensions. Different ones of the phosphor areas are capable of producing light of the component image colors when excited by electron beam energy. In this tube, the diiferent light-producing phosphor areas are excited respectively by a plurality of electron beams, or by a plurality of components of a single beam, approaching the screen from different angles through an apertured electrode. Color selection is secured by the angle at which the electron beam components approach the screen. A tube of the kind described forms :the subject. matter of U.S. Patent 2,595,548 granted May 6, 1952, to Alfred C. Schroeder for Picture Reproducin-g Apparatus.

The expression electron beam components as used in this specification and claims will be understood to denote the phosphor-exciting electronic energy produced either by a single, or by` a plurality of, electron guns. This energy may be continuous or pulsating as required without departing from Vthe scope of the invention. An example of a color kinescope in which different components of a single electron beam aroused to exciteV a phosphor screen ofthe kind described is disclosed in a paper by R. R. Law, titled A One-GunShadow-Mask Color Kinescope published in the Proceedingso'f the IRE, vol. 39, No. l0, October 1951, at page 1194.v Such a tube forms' the subject matter of a copen-ding U.S;\patent applicationof RussellR. Law, Serial No. 165,552, tiledv June 1, 1950, and titled Color Television '(now .abandoned).

The successful operation of ya multi-color kinescopeof the type referred to requires that the plurality ofelectr'on beam components be made to converge ysubstantially at the apertured electrode atlall points in the scanned raster. ln view of the fact that the different points of such a target electrode are at different distances from Ithe point or region of the electron beam deflection, it is necessary to provide a field-producing means which is variably energized to produce the desired dynamic convergence control. One such electron beam control system is disclosed in a paper by Albert W. Friend titled Deection and Convergence in Color Kinescopes published in the Proceedings of the IRE, vol. 39, No. `10, October 1951 atv page 1249. Such a system forms the subject matterv of a vcopending U.S. patent application of Albert W. Friend, Serial No. 164,444, filed May 26, 1950, now Patent No. 2,751,519 granted June 19, 195,6, and titled Electron Beam Controlling System. In the system proposedlby Friend, electron-optical apparatus is energized both stat- 2,999,186 *n FatentedSept. 5,' 1961 ically and dynamically to produce rthe desired result. By means including the static energization of the electron-optical apparatus, theFriend system effects initial convergence of the electron-beam components substantially at the center of the raster to be scanned. The dynamicenergizationof the electron-optical apparatus is yeffected as functions offboth the horizontal and vertical 1 beam deflections. Essentially these functions are parabolic. In the Friend and other systems previously employed, vsomewhat complicated apparatus has beenrequired vto produce the desired energizing waveforms.'

Therefore, it is an object of this invention to provide improved and simplified apparatus by which to develop waveforms for the dynamic energization of an electron beam-controlling system for a multi-beam kinescope.

Another object of the invention is to provide improved apparatus lby'which to develop waveforms for effecting both static and dynamic convergence of the electron beam eor'nponentsfof a multi-beam kinescope.y

The present invention isV employed in Ya' beam convergence system wherein use is made Vof Aa substantially sinusoidal wave for energizing thel field-producing means -by which the convergence isle'ieoted instead of thetheoduce the proper sinusoidal Waveform by which `to `energizethe convergence apparatus.

In accordance with the present invention, there is provided an improved system by which to energizethebeam convergence field-producing apparatus. This improved systemincludes one or vmore circuits each including Va coil and a capacitor tuned respectively to one or more of the frequencies of the deflection Wave apparatus ly Awhich (the electron beams are deflected for kraster 'scanning purposes.. One of the features ofthe .present inventionis the additional use of the tuned circuit coilas part of the` beam convergence held-producing apparatus.

VWhen such a tuned circuit Vis coupled to the" deeetion wave :apparatus for excitation thereby, a 'substantially sinusoidal wave is produced at the deflection Wave frequency.Y Thevpresentinvention may be employed for velfectingbearn convergence at either or -both ofthe horizontal and-vertical deflection frequencies. For the purpose of effecting beam convergence at horizontal'deilec- -tion frequency, there is provided a beam convergence coil for field-producing purposes. In order to effect beam convergence a-t theveitical deflection frequency, arr'elecf tro-magnetic focusing coil is part of thel tunedi'circuit.

In this case, the focusing coil may provide Yallor Aonly a part of the energy for producing a beam focusing field.

Either or both ofthese tuned circuits may be energized byf exciting them-with periodic waves of suitablerfor'm 'such as parabolic waves or waves having a` pulse conjrponent, for example.

The novel features that are considered characteristic of this inventionare set forth With particularity in the' appended claims. The inventicnitself, howeven'bothv as toits organization and method of operation', a's well as additional objects and advantagesv thereof, will best be understood from the following description when read in connection with the accompanying drawings. \In the drawings: v

y 1 is algeneral circuit diagram offa vcolortelevision receiver employing a tricolor kinescope, partly in block and partly in schematic form, and showing an illustrative embodiment of the invention;

FIGURE 2 is `a fragmentary schematic circuit diagram of a portion of a color television receiver embodying a form of the invention which may be employed with tricolor kinescopes having electrostatic eld-producing apparatus for eiecting beam convergence;

FIGURE 2a is a fragmentary schematic circuit diagram which is a modioation. of FIGURE 2 using the beam focusing coil as one of the inductive elements;

FIGURE 3 is a fragmentary circuit diagram showing an alternative way of producing the desired convergence wave energy at vertical deection frequency;

FIGURE 4 is a fragmentary circuit diagram of an alternative way of energizing the convergence wave producing apparatus at horizontal deflection frequency in accordance with the invention; and

FIGURE 5 is a circuit diagram showing still another way of energizing the horizontal convergence waveproducing apparatus in accordance with the invention.

Reference first will be made to FIGURE 1 of the drawings for a general description of a color television receiver showing an exemplary embodiment of the invention. The television receiver may be generally conventional and includes an antenna 11 to which is coupled a conventional television receiver 12. It will be understood that the receiver 12 may include such usual apparatus as carrier wave ampliers at both radio and intermediate frequencies, a frequency converter and a carrier wave demodulator or signal detector. Accordingly, it will be understood that both video and synchronizing signals are derived from the receiver 12. The video signals are impressed upon a video signal channel 13 and the synchronizing signals are. impressed upon a sync signal separator 14. It will be understood that the video signal channel includes apparatus for deriving from the video signals appropriate red, green and blue representative video signals for use in reproducing an image in color. Since such apparatus does not form any part of, nor is considered necessary to understand, the present invention, it has not been specifically illustrated. It also will be understood that the sync signal separator 14 is conventional apparatus such as described in U.S. Patent 2,207,775 granted to A. V. Bedford July 16, 19,40. The general purpose of such apparatus is to separate the horizontal and vertical synchronizing signals from the video signal component of the composite television signal and also from one another. It, therefore, will be understood that the horizontal synchronizing pulses are developed in the output circuit HORIZ of the sync signal separator and similarly the vertical synchronizing signals are developed in the output circuit VERT.

In this illustrative embodiment of the invention, it is assumed that the red, green and blue representative video signals R, G and B respectively which are derived from the video signal channel 13` are impressed upon the electron beam controlling apparatus, generally referred to -as the electron gun apparatus, of a tricolor kinescope 15. This kinescope may be of the same general type disclosed in the H.B. Law paper previously referred to. An alternative form of a three beam tricolor kinescope of this same general type is one in which the three beams are developed by means of electron gun apparatus having an electrode provided with three apertures suitably positioned and from which the three beams emanate. Such electron gun construction enables the three produced electron beams to be more closely spaced relative to one another around the central aXis of the kinescope than in a form of kinescope such as the three gun apparatus specifically described in the H.B. Law paper. Another type of tricolor kinescope with which the present invention may be employed is that described in the aforementioned R.R. Law paper. In any case, however, the kinescope has a luminescent screen 16 which may be substantially at as shown and which is provided with a multiplicity of small phosphor areas arranged in groups and capable respectively of producing light in the diiferent primary colors in which the image is to be reproduced when excited by electron beam energy. In back of and spaced from the screen 16 there is an apertured masking electrode 17 having an aperture for and in alignment with each group of phosphor areas of the Screen 16. It will be understood that the electron gun structure of ithe kinescope 15 is of a suitable character to develop electron beam components 18, 19 and 20 which are caused to approach the target electrode structure including the luminescent screen 16 and masking electrode 17 from three different angles in order to excite three dijerent colored light producing phosphors. For convenience of illustration, the angles at which the electron beam components approach the target electrode structure has been greatly exaggerated.

The color kinescopeplS also is provided with a deection yoke 21 which may be of a conventional character. In general, it consists of a pair of interconnected coils forming a horizontal deection winding which is brought out to a pair of terminals H and another pair of coils forming a vertical deection winding which is brought out to a pair of terminals V. 'Ihe yoke is mounted around the neck of the kinescope in the region adjacent to the point at which the neck joins the conical section of the tube.

'Ihe kinescope 15 also is provided with an electromagnetic focusing coil 22 which is located generally to the rear of the deection yoke Z1. In this form of the invention, it is assumed that the coil ZZ eiects the desired focusing of the individual electron beams, as indicated. The winding of the focus coil is brought out to a pair of terminals F. In addition, the kinescope 15 is provided with a convergence coil 23` which is located generally in the region between the focus coil and the deection yoke. The convergence coil is wound in such a way as to produce an electro-magnetic field of a character to change the angles at which the electron beams approach the deliection region within Vthe yoke 21 and thereby to eiect a corresponding change in the convergence angles of these beams at the target electrode structure, particularly in the plane of the masking electrode 17. The winding of the convergence coil Z3 is brought Aout to a pair of terminals "C.

Both the horizontal and vertical windings of the deilection yoke 21 are energized in a substantially conventional manner for the purpose of deflecting the electron beams 18, 19 and Z0 together so as to scan a raster in the plane of the target electrode structure including the luminescent screen 16. In the case of the horizontal .deection winding, the horizontal sync signals are impressed upon a vhorizontal sweep oscillator 24 for the purposeof synchronizing it. 'Ihe sweep oscillator produces a substantially sawtooth Wave which is impressed `upon the input circuit of a horizontal oultput electron tube 25. The output circuit of this tube includes a horizontal deilection output transformer 2.6 having a primary winding 27 coupled to the output tube 25 and a secondary winding 28 coupled to the horizontal winding of the .detlection yoke Z1. It will be understood that an autotransformer in which the yoke lWinding is connected to taps on the same transformer winding that the output tube is connected to may be used, if desired.

'I'he high voltage terminal of the horizontal output transformer primary winding 27 is connected to a diode rectifier tube 29 to produce a high voltage from the iiyback pulses developed in *this transformer during retrace periods for use in supplying the high voltage necessary for some of the kinescope electrodes such as the iinal anode, or ultor, 31. Also, the horizontal deection output circuit includes a diode damper tube 32 connected to the horizontal yoke winding in a conventional manner so as to damp unwanted osoillations'in the yoke winding during horizontal retrace intervals and also to utilize the absorbed energy to supply boostedB potentiaLfwhen ltered suitably by a iilter 33` connected to the damper tube. In this case, the boosted Brpotential isimprcssed upon the anode of the horizontal output tube asv indicated. Such horizontal deflection output .apparatus v'is conventional.

The vertical dellection circuits also are conventional and include a vertical sweep oscillator 34 which produces a substantially sawtooth wave atvertical deflection frequency and which is synchronized bythe vertical synchronizing signals derived from the sync signal separator 14. The vertical sweep oscillator is coupled to the input circuit of a vertical output electron tube 35. The output circuit of this tube is coupled by means including a vertical output transformer 36 to the vertical winding of the deflection yoke Z1.

In accordance with the pres-ent invention, the illustrative embodiment thereof shown in. FIGURE 1 employs the winding of the focus coil Z2 as a part of a tuned'circuit which includes additionally a capacitor 37. This part of the circuit is tuned for parallel resonance at the vertical deection frequency. There is impressed upon this circuit a Wave such as the substantially sawtooth vertical essaies d'eection Wave 38 having also a peaking pulse compov nent 39. Such a wave is developed at the anode of the vertical output tube 35 and, in addition to being impressed upon the vertical delection yoke winding, is coupled by a capacitor 40 and a variable resistor 41 tothe tuned circuit including the focus coil 22 and the capacitor 3 7. The capacitor 40 serves as la D.C. blocking capacitor and the resistor 41 is an isolating resistor which may be employed as an amplitude control for the vertical dynamic convergence field component by suitably varying the amplitude of the wave 38 which is impressed upon the tuned circuit. By means of the tuned circuit a voltage amplication is elfected so that the sinusoidal. voltage Wave 42 which is developed across Ituned circuit is suliicient in amplitude and is of the proper phase to produce suitable current variations through the focus coil 22 to effect the desired dynamic beam convergence at the vertical deection frequency. In one operative embodiment of this form of the invention which has been successfully employed, approximately 100 milliamperes of direct current is passed through the focus-.coil 22 in order to provide the initial static beam focus and beam convergence lield. This current is derived from a relatively low impedance source. In order to prevent this source from effectively short circuiting lthe sinusoidal beam convergence voltage produced in the manner described, a choke coil 43 is employed and connected as shown. The choke coil and the capacitor 37 form a parallel tuned 4circuit at the vertical deection frequency. VThe proper a series tuned circuit which also includes a capacitor 44.

This circuit is tuned for resonance at the horizontal deflection frequency. The circuit is energized by a voltage impressed upon the capacitor 44 and which is derived from another series tuned circuit including an inductor 45 and a capacitor 46. This circuit also is tuned for resonance at the horizontal deliection frequency. Each of these. series tuned circuits eifects a voltage amplification of -a substantially parabolic. voltage wave 47 derived from the cathode circuit of the horizontal output tube 25. The parabolic voltage Wave -47 is impressed upon ythe series tunedcircuits through an adjustable isolating resistor `48. The cathode circuit of the horizontal output tube includes a resistor 49 and a vbypass capacitor 51 which function as an integratingnetwork to convert the substantially sawtooth wave impressed upon the lgrid circuit of the horizontal output tube into the substantially parabolic Wave 47. This wave is' converted by means of the series timedcircuit including-the inductor 45 andcapacitor 46 to a substantially sinusoidal Wave at the horizontal deflection frequency., `The relatively high sinusoidal voltagedeveloped across theV inductor` 45', in` turn,

drives ,the series 'tuned circuit including the convergence coil Z3 rand capacitor 44in such la" manner thatthe'gsubstantially sinusoidal voltage 52 developed across theconvergence coilV is suitable to produce lthe desired current variations in this coil to effect dynamic convergence of the electron beams 18, 19 and 20 -at the horizontal deliec-` tion frequency.

The adjustable isolating resistor 48 is employed to effect anj amplitude control for thehorigontal dynamic convergence wave. Proper phasing lofmtlie horizontal' convergence wave 52 relative tofthe horizontal beam deection may be obtained Aby, adjusting the tuningof either one-of the, series tuned circuits suchrasby means of the variable inductor 45.- Inasmuch as the voltage and current relationships inY these` circuits are approximately 90 out of phase, in some cases it may bef-helpful to provide `a third series tuned circuitsimilar to either of those shown in order to obtain the proper phasing of the convergenc current inthe coil 23. 'n

It should'be noted that the use of the tuned circuits for electing both horizontal and vertical dynamic beam convergence may be advantageously employed with tricolorV kinescopes which have electrostatic beam focus and convergence field-producing apparatus. A representative example of such apparatus is shown in FIGURE 2, to which reference now will be made. In this and all of the remaining figures' of the drawings, the same characters of references will be used withvrespect to corresponding apparatus in the various gures. In this case, the tricolor kinescope 15 is provided with a convergence anode 53 which is located adjacent to the conductive wall coating 31, serving as the final anode, or ultor, of the kinescope. The impression of dilferent potentials upon these two electrodes produces an electron-optical lens which determines the convergence angles of the electron beam components. By varying one or both of these potentials relative to one another, the convergence angles of the beams may be changed. In this form, of the invention, the potential of the'ultor electrode 31 is maintained xed and the potential of the convergence anode 53 is varied as a function of the horizontal Iand vertical beamtdeilection anglesi To effect the dynamicV variation of the convergence anode potential at vertical deflection frequency, a sub*- stantially parabolic wave 54 derived from the cathode circuit ofthe vertical deflection output tube 35k is impressed -by means ofthe blocking capacitor 40 andI the isolating resistor 41 upon a parallel tuned circuit including-an inductor 5S land the tuningcapacitor 37. The in4 ductor`55 and the tunin'gcapacitor 37 comprise a circuit which is resonanttat the vertical deflection frequency to produce a substantially sinusoidal Wave 56 in response to the excitation thereof by the parabolic wave 54.v The` sinusoidal wave 56 is impressed by means including a coupling capacitor 57 upon the convergenceanode 53.

YThe parabolic yWave 54is produced in the cathode circuit l of the vertical deflection outputtube 35 b y means of an integrating process performed` by a Variable cathode resistor 5S,V serving as a vertical deflection linearity control, and a bypass capacitor 59 upon .a substantially sawtooth Wave impressed upon the control grid 'o'fr'this tube.

In a somewhat similar manner, the horizontal parabolic wave 47 is impressed by the isolatingV resistor 48 upon the series tuned circuit including the capacitor 46'` and vthe inductor 45 as in 'theV embodiment of the invention shown in FIGURE 1. Also, the first series tuned circuit is coupled to a second series tunedV circuit including the capacitor 44 and an inductor 60 substituting for the con- Accordingly, there i s produced a-substantially sinusoidal wave 61 across the-in- 7 ductor 60 which is impressed by acoupling capacitor 62 upon the convergence anode 53 of the kinescope 15.

The composite potential Wave 63 impressed upon the `convergence anode 53 consists essentially of the direct addition. of the vertical frequency sinusoidal wave 56 and the horizontal frequency sinusoidal wave 61. This composite wave 63 is, in effect, superimposed upon a unidirectional potential impressed upon the convergence anode and derived from a potentiometer 64 connected in a bleeder circuit across the high voltage supply derived from the diode 29. As has been stated, either or both of the horizontal and vertical frequency tuned circuits may be energizedA by excitation with periodic waves of parabolic shape or waves having a pulse component. Thus, as shown in FIG. 2a, the focus'coil 22 is energized with a parabolic wave of ventical frequency from the cathode of the vertical output tube 35 and the convergence coil 23 is energized with la parabolic wave of horizontal frequency from the cathode of the horizontal output tube 25. It will be recognized that FIG. 2 differs from FIG. 2a 'only in that the focus coil 22 in the latter constitutes the inductance 55 of the former.

Another form of the invention isillustrated in FIGURE 3. Although not necessarily limited thereto, such an embodiment is particularly useful with a tricolor kinescope in which a major part of the individual beam vfocusing is effected by means of a permanent magnet Y65. In this case, the kinescope is provided with an electromagnetic focus coil 22a serving to provide a limited beam focusing action and also to eiect dynamic beam convergence at vertical dellecttion frequency. In this case, the focus coil 22a is energized by a connection to the secondary Winding 66 of a coupling transformer 67 having also a primary winding 68 connected to the anode circuit of the vertical deflection output tube 35. The primary Winding 68 is tuned for resonance at the vertical deection frequency by means of a shunt connected capacitor 69. By such means, the substantially sawtooth deection wave 38 having a peaking pulse component 39 is converted by the tuned primary transformer winding to a substantially sinusoidal wave which is coupled to the focus coil 22a for dynamically energizing it for the purpose of effecting beam convergence at the vertical deflection frequency.

FIGURE 4 illustrates another embodiment of the invention for electing the desired dynamic beam convergence control at horizontal deflection frequency. In this case, the convergence coil 23 -forms a part of a combination series and parallel tuned circuit. A capacitor 71 effects the series tuning of the convergence coil 23 at the horizontal deflection frequency and the variable capacitor 72 effects the parallel tuning of the convergence coil at this frequency. In this case, the combined series and parallel tuned circuit is energized by a substantially parabolic wave 73 derived in this case from the cathode of the damper tube 32. A series adjustable resistor 74 connected in the ground return of the series tuned circuit is employed to vary the damping of the circuit and thereby to provide an amplitude control of the convergence at horizontal dellection frequency. The adjustable parallel tuning capacitor 72 enables the proper phasing of the developed sinusoidal wave relative to the horizontal beam deflection.

It will be understood that an arrangement of the character described using a combined series and parallel tuned circuit may be employed for electing dynamic beam convergence using an electrostatic convergence system such as that illustrated in FIGURE 2. In such a case, the convergence coil 23 wouldA be replaced by an equivalent inductor and the sinusoidal voltage developed across such an inductor would be capacitively coupled to the convergence anode in a manner similar to that shown in FIGURE 2.

FIGURE 5 illustrates still another embodiment of the invention in which a combined series and parallel tuned circuit-including a convergence coil 23 similar tothat shown in FIGURE 4 may be excited to produce the desired dynamic beam convergence at horizontal dellection frequency. In this case,A the combined series and parallel resonant circuit is excited by a substantially pulsating wave in which the pulses occur at the horizontal deectionfrequency. -Suchpulses are produced in the circuit Vconnecting the secondary'winding 28 of the horizontal deflection output transformer 26` to the horizontal winding of the detlectionyoke 21.V In the particular circuit illustrated, this point lsois connected to the anode of the damper tube 32. "Ihe combined parallel tuned circuit functions to convert the pulsating wave 75 into the desired substantially sinusoidal Wave 52.

It may be seen from the foregoing illustrative embodiments of the invention that there is provided an improved and simplified apparatus by Awhich to develop the waveforms for dynamic beam convergence in a multibeam 'kinescope By utilizing theelectromagnetic feldproducing apparatus of the kinescope, the desired wave- Yforms may be produced by utilizing other waveforms existing in the circuit at the desired frequencies'but in undesired forms. The employment of series tuned circuits elects a voltage ampliiication, there by obviating the use of additional electron tubes. It, therefore, is unnecessary to employ complicated apparatus for developing the desired waveforms and foramplifying such waveforms. -The present arrangement also provides a relatively simply apparatus which is arranged in such a manner that there is produced the desired "v phase relationshipbetween the current and the dynamic beam convergence by electromagnetic means.

The invention having been described in number of illustrative embodiments, its scope is pointed out in the appended claims. 7

What is claimed is: y

l. In a cathode ray image-reproducing system wherein a plurality of electron beam components, which traverse predeflection paths that are spaced respectively about the longitudinal axis of a tube, are angularly deflected both horizontally and vertically to scan a raster at a target electrode and having field-producing apparatus adjacent to said predeection paths and energizable to effect substantial convergence of said beam components at -al1 points of said raster, a. system to energize said eldproducing apparatus comprising, raster-scanning dellect-ion wave apparatus, a first tuned circuit including a coil and a capacitor tuned to the operating frequency of said deflection wave apparatus, said coil forming at least part of said beam convergenceV field-producing apparatus, and means including a second tuned circuit tuned to the operating frequency of said deflection wave apparatus coupling said rst tuned'circu'it to said deflection wave apparatus to develop and apply to said coil substantially sinusoidal beam convergence wave energy at the operating frequency of said deection wave apparatus.

2. An energizing system for beam convergence fieldproducing apparatus as defined in claim 1 wherein, said deflection wave apparatus operates at vertical deflection frequency, and said coil compnises at least part of the beam-focusing apparatus of said cathode ray tube 'apparatus.

3. An energizing system for beam convergence eldproducing apparatus as defined lin claim 1 wherein, said deflection wave apparatus operates at horizontal deection frequency, and said coil comprises an electromagnetic beam convergence coil. Y 4. In a cathode ray image-reproducing system wherein a plurality of electron beam components, which traverse predeflection paths that are spaced respectively about the longitudinal axis of a tube, are angularly deected both horizontally and vertically to scan a raster at a target electrode and having held-producing apparatus adjacent to said predeflection paths and energizable to `eiect subcoupled to said vertical deflection apparatusto develop substantially sinusoidal convergence wave energy at'said vertical deflection frequency,v a series tunedfcircuit coupled to said horizontal deflection apparatus to develop substantially sinusoidal beam convergence wave.' energy at said horizontal deflection frequency, each of said tuned circuits including a coil, and said coils forming at least part of said beam convergence field-producingapparatus.

5. An energizing system for beam convergence eldproducing Yapparatus as defined in claim 4;,wherein, one of said tuned circuits is coupled to its associated deflection apparatus at a point producing a substantially parabolic wave. n

6. An energizing system for beamconvergence fieldproducing apparatus as dened in claim V4 wherein, one of said tuned circuits is coupled toits associated deflection apparatus at a point producing a4 wave having a pulse component. Y

7. An energizing system for beam convergence fieldproducing apparatus as defined in claim 4 wherein, both of said tuned circuits are coupled to their 'associated deection apparatus at points producing substantially parabolic waves. c

8. An energizing system for beam convergence vfield'- producing apparatus as defi-ned in claim Vi wherein, rboth Y.

of said tuned circuits areecoupled to their `associated deflection apparatus at points producing waves having pulse components. Y

9. An energizing system for convergence fieldproducing apparatusfas defined in-claim 4Wwherein, said twotuned circuits are coupled tovtheir associatedudeection apparatus at points producinggrespectively aj substan-tially parabolic wave and a waveshaving-'aj p ulse component. e 1 1 10. In a cathode rayirnage-reproducing system wherein aplurality of electron beam components, whichtraverse predeection paths that are spaced respectively4 about the longitudinal axis of a tube, -are angularly deflected both horizontally andY-verticallyto scana` raster at a target electrode and having iieldeprodcin'g'.apparatus adjacent to said predeflection paths -andenergizable toe'iect substantial convergence of said beam components at all points of said raster, a system to energize said fieldproducing apparatus comprising, horizontal and vertical deliection wave apparatus, a focus coil and a convergence coil comprising said field-producing means, means including a capacitor connected in shunt with said focus coil and forming therewith a parallel tuned circuit at said vertical deflection frequency, means coupling said parallel tuned circuit to said vertical deflection apparatus to effect said beam convergence at vertical deflection frequency, means including a capacitor connected in series with said convergence coil and forming therewith a series tuned circuit at said horizontal deflection frequency, and means coupling said series tuned circuit to said horizontal deflection apparatus to effect said beam convergence at horizontal deliection frequency.

1l. An energizing system for beam convergence fieldproducing apparatus as dened in claim l0 wherein, said parallel tuned circuit is coupled to said vertical decction apparatus at a point producing a substantially sawtooth wave having a peaking pulse component.

l2. An energizing system for beam convergence fieldproducing apparatus as defined in claim 10 wherein, said series tuned circuit is coupled to said horizontal deflection apparatus at a point producing a wave having a pulse component.

13. An energizing system for beam convergence fieldproducing apparatus as defined in claim 10 wherein, said series tuned circuit is coupled to said horizontal deliection 'l5 annonc Y l0 apparatus at a point producing a substantially parabolic Wave.`

14. An energizing system for beam convergence'eldproducing apparatus as .defined inclaim 10 wherein, said parallel tuned circuit is coupled to said vertical deection apparatus at. a point producingza substantially Vsawtooth wave having a peaking pulse component, and said series tuned circuit is coupled to said horizontal deflection appaf ratus at a point producing a substantially parabolicwave.

15. -An energizingl system for beam convergence eldproducingapparatusras defined in claim- 10 wherein, said coupling `means between said series tuned circuit and saidihorizontal deflection apparatus includes an additional series tuned circuit atl said horizontal deliection frequency. 16. In al television receiver Vincluding va cathode ray image lreproducing tube jhavingrneans for developing at least one cathode ray beam ytherein andfmeans for controlling ther convergence of such beam, and a sweep systemfor supplyingto the cathode ray tube a deflection signal of aselected frequency for'scanning the cathode raybeam, a circuit for developing a convergence control signal forV dynamically controlling the convergenceof the cathode ray beam Vthroughout eachecycle ofthe dellection signal, said circuit including in combination, a resonant network having arst resonant section coupled to the sweep system for-producn-g a iirst'sine wave signal in response to exciting-pulses from the sweep system, said sine wave signal being in phase quadrature with the exciting pulses and of increased amplitude relative thereto, said network. also having a second resonant section coupled to said lirst section for producing a second sine wave signal inphase quadrature with said first sine Wave Signal and ofYinc-reaysed amplitude relative thereto, and means forutilizing'y said-second sine wave signal to `supply a. dynamic convergence control signal to the convergence controlling means of the Yreproducing tube.

17.In a television receiverA including a cathode-'ray imago-reproducing tube having means forV developing at least one cathode ray. beam therein and means for controlling theconvergence of such'beam, and afsweep system for supplying to the cathoderray tube adeliection signal: of `a VselectedV frequency for scanning the'cathode ray beam', acircuitgfor developing a convergence control signal. for; dynamicallyl controlling theV convergencefof the cathode ray beam throughout each cycle of the deflection signal, said circuit including in combination, a resonant network having an input terminal and an output terminal, means for coupling said input terminal to said sweep system, said resonant network including a first series resonant section comprising a capacitor and any inductance coil series connected between said input -ter-V minal and a point of reference potential, said network further including a second series resonant section lcornprising an inductance coil and a capacitor series connected from the common junction of said inductance coil and capacitor of said first section to said point of reference potential, means for coupling said output terminal to the common junction of said inductance coil and capacitor of said second section, and means for coupling said resonant network to said convergence controlling -Ineans of the image reproducing tube.

18. In a television receiver including a cathode ray image reproducing tube having means for developing at least one cathode ray beam therein and ra sweep system for supplying to the cathode ray tube a deection signal of a selected frequency, a circuit fordeveloping a convergence control signal for dynamically controlling the convergence of the cathode ray beam throughout each cycle of deliection, said circuit including a resonant network having frst and second tuned circuit portions, said first tuned circuit portion of said resonant network bein-g coupled to said sweep system and beingV tuned to said selected frequency, said second tuned circuit portion being coupled to said first circuit portion and developing a' 1'1 convergence control signal substantially at the selected frequency for converging the cathode ray beam.

19. In a color television receiver including a cathode ray image reproducing tube having means for developing av plurality of cathode ray beams therein, a sweep system including a transformer for' supplying in the cathode ray tube a field for dellecting said beams at a selected frequency, said transformer of said sweep sysltem having a winding in which a pulse wave is developed, and a convergence system for providing a lield in the cathode ray tube for converging the cathode ray beams, said convergence system including a circuit for developing a eld component the cathode ray tube for dynamically controlling the convergence of the cathode ray beams throughout each cycle of deflection, said circuit including, a resonant network having first and second tuned circuit portions, said irst tuned circuit portion being tuned to said selected frequency and coupled to said Winding for deriving energy therefrom, said second tuned circuit portion being coupled to said rst tuned circuit portion and producing the iield component for dynamically converging the cathode ray beams.

20. In a color television receiver including a cathode ray image reproducing tube having means for developing a plurality of cathode ray beams therein and means for controlling the convergence of such beams, and a sweep system for supplying to the cathode ray tube a deection signal of a selected frequency for scanning the cathode ray beams, a circuit for developing a convergence control signal for dynamically converging the cathode ray beams throughout each cycle of the deection signal, said circuit including in combination, an amplifier valve coupled to the sweep system and having an output element at which appears a signal of substantially the selected frequency, a resonant network including iirst and second tuned circuits coupled to said output element, said first and second tuned circuits being resonant at 4frequencies bearing a predetermined relation to the selected frequency, and means for coupling said resonant network to the means for controlling the convergence of the beams in the reproducing tube.

21. In a cathode ray image-reproducing system wherein a plurality of electron beam components, which traverse predeilection paths that are spaced respectively about the longitudinal axis of a tube, are angularly deected both horizontally-and vertically to scan a raster at a target electrode, and having field-producing apparatus adjacent to said `predellection paths and energizable to effect substantial convergence of said beam vcomponents at all points of said raster, a system to energize tus, said means Aforming at least part of said beam convergence field-producing apparatus, and means including a second tuned circuit tuned -to the operating frequency of said deection Wave apparatus coupling said first tuned `circuit to said deection Wave apparatus to develop and Aapply to said coil substantially sinusoidal beam convergence wave energy at the operating frequency of said deliection Wave apparatus.

22. Dynamic convergence apparatus for a color television tube operable by multiple electron beams converging to Aai common point, said apparatus comprising, an electromagnet responsive to current in a circuit for deflecting one of said electron beams as a concomitant to shifting said convergence point in the tube axis direction, a capacitance coupled with said electromagnet in tuned relation with the inductance of said circuit to render said circuit oscillatory at horizontal scanning frequenscy, and a source of iyback pulses coupled with said capcitance and electromagnet in series for shock exciting said circuit into generating oscillations in the form of cosine current through said electromagnet during horizontal scanning periods.

References :Cited in the le of this patent UNITED STATES PATENTS OTHER REFERENCES Article by Friend in the Proceedings ofthe I.R.E., vol. 39, October 1951, pp. 1249-1263. 

